Gas treatment devices such as catalytic converters, evaporative emissions devices, hydrocarbon scrubbing devices, diesel particulate traps, non-thermal plasma reactors, and the like, are employed in various applications to catalytically treat environmentally unfriendly gas components. Such gas treatment devices incorporate a substrate, support, monolith, or brick, which includes a catalyst material coated thereon. A mounting device such as a mat support material comprising an intumescent material, non-intumescent material, or a combination of both, is disposed about the substrate, e.g., a mat support material/substrate subassembly, prior to being inserted into the gas treatment device's housing or shell. One method for inserting the mat support material/substrate subassembly into the housing comprises using a stuffing cone.
FIG. 1 illustrates a cross-sectional view of a stuffing cone 10 attached to a housing 12 for a gas treatment device. The stuffing cone compresses the abrasive, ceramic mat support material about the substrate so that the subassembly can be disposed into the housing. More particularly, as the mat support material/substrate subassembly slides against the inwardly tapered interior of the stuffing cone, the mat support material compresses about the substrate. As the mat support material compresses, it erodes the tapered interior of the stuffing cone. Eventually, the stuffing cone loses its ability to compress the mat support material about the substrate. Thus, stuffing cones are designed to have thick sidewalls, which narrow the diameter of the opening designed to attach to the housing.
Generally, the stuffing cone's diameter is less than the diameter of the smallest housing to compensate for the increased thickness of the stuffing cone's sidewalls. This design change causes the mat support material to exert over approximately six hundred pounds per square inch of force about the substrate. In contrast, it is predicted that the housing exerts over approximately one hundred pounds of pressure per square inch about the subassembly to retain it in place after disposal. The additional pressure exerted during the subassembly's compression in the stuffing cone reduces the mat support material's retentive capabilities, increases the over compression of the mat support material, and increases the probability of substrate breakage.